1. Evolution
A process of change through time in which a new species comes about from a preexisting species

2. Indirect vs. Direct Evidence
Indirect Evidence:
Fossils: the remains and traces of organisms that once lived.
It shows that through time organisms have changed from one form to another. Suggesting a common ancestor.

3. Formed by:
Preservation:
Iceman
Tar Pits

4. Actual Skeletons:

5. Imprints:

6. How are Fossils Formed? Sedimentary Rock
Tiny grains of eroded rock and other materials that settle

7. Two Types of Dating Relative Dating:
Comparing the stratum of sedimentary rock with other strata.
Oldest??
Most complex??

8. The Grand Canyon

9. Absolute Dating: Carbon 14 Dating Radioactive Dating:
estimation of the actual age of a fossil by measuring how fast radioactive elements break down into nonradioactive elements.
Carbon 14 Dating
Only for fossils that contain Carbon.
40,000 years and younger.
Wood, charcoal, marine ,freshwater shell, bone,antler, peat ,organic-bearing sediments, carbonate deposits such as calcite, dissolved carbon dioxide, and carbonates in ocean, lake, and groundwater sources.

10. How is Carbon 14 produced?

11. Age determined by half-life
The time it takes for ½ of a radioactive material to decay to its nonradioactive form.
Carbon Half-life = 5730 years.
Full Amt ½ left ¼ left /8 left /16

12. Half – Life of other Substances
Uranium 238 – Lead 206
Uranium 235 – Lead 207
Carbon 14 – Nitrogen 14
Oxygen 19 – Oxygen 16
Potassium 40 – Argon 40
4.5 Billion Years
713 Billion Years
5730 Years
19 Seconds
1.5 Billion years
m&m Half-Life Activity!!

13. Activity

14. 2. Darwin's Finches
Darwin speculated that birds, resembling starlings, came to the Galapagos Islands by wind. Evolution took over and different groups developed different diets. When, he wrote, "an immigrant first settled on one of the islands, ... it would undoubtedly be exposed to different conditions in the different islands (where) it would have to compete with a different set of organisms. ... Then, natural selection would probably favor different varieties in the different islands."

15. The Galapagos Islands

16. Correlation of species to food source
Seed eaters
Flower eaters
Insect eaters
Rapid speciation: new species filling niches, because they inherited successful adaptations.

17. Beak variation in Galapagos finches
(a) Cactus eater. The long, sharp beak of the cactus ground finch (Geospiza scandens) helps it tear and eat cactus flowers and pulp.
(c) Seed eater. The large ground finch (Geospiza magnirostris) has a large beak adapted for cracking seeds that fall from plants to the ground.
Conclusion: Suggests a common ancestor.
Very similar birds but beaks varied considerably.
(b) Insect eater. The green warbler finch (Certhidea olivacea) uses its narrow, pointed beak to grasp insects.

18. 3. Comparative Anatomy Anatomical evidence
1. These structures are called… homologous
2. These structures are evidence for…. common ancestry
3. similar internal structure = similar development
4. different function = different environment & niche
5. close evolutionary r’ship!

19. Comparative Anatomy: Study which compares body parts from different species
Homologous Structures: Similar structure, different function. (Suggests a common ancestor)

20. Analogous structures Similar function, different structure.
same function different development & anatomy
Those fins & tails & sleek bodies are analogous structures!
convergent evolution - NOT common ancestor
Solving a similar problem with a similar solution

21. 4. Vestigial organs
These are remnants of structures that were functional in ancestral species
Suggests common ancestry.
Remains of ancestral structures = mutations can occur without affecting survival & reproduction
Evolutionary relationship
snakes & whales — remains of pelvis & leg bones of walking ancestors
eyes on blind cave fish
human tail bone

22. 5. Comparative Embryology
Organisms are similar to each other early in their development, slowly differing . Indicating a common ancestor.

23. 6. Comparative Biochemistry
Comparing the differences between Protein or DNA Sequences
Why compare DNA & proteins across species?
The sequence in DNA & proteins is a molecular record of evolutionary relationships. 10 20 30 40 50 60 70 80 90
100
110
120
Lamprey
Frog
Bird
Dog
Macaque
Human 32 8 45 67
125
Comparative hemoglobin structure
Molecular Record
What are we comparing here? - comparing DNA (base sequence) & proteins (amino acid sequence)
What assumption do we make about genes and relatedness?  the more closely related, the more DNA bases & amino acids you have in common
have to compare genes for protein the organisms have in common… can’t compare genes for proteins you don’t have
Genetic differences are interpreted as indication of how much evolution has taken place.
compare common genes
cytochrome C (respiration)
hemoglobin (gas exchange)

24. 7. Geographic Isolation: Species have been isolated by a physical barrier and cannot interbreed any more. Indicating slow change.

25. Direct Evidence for Evolution
1. Peppered Moth
Coloration fluctuated over 100 years due to environmental change in tree trunks.
Year % dark % light

26. Peppered moth What was the selection factor?
B. Kettlewell
What was the selection factor?
early 1800s = pre-industrial England
low pollution
lichen growing on trees = light colored bark
late 1800s = industrial England
factories = soot coated trees
killed lichen = dark colored bark
mid 1900s = pollution controls
clean air laws
return of lichen = light colored bark
industrial melanism

27. 2. Antibiotic Resistance: Bacteria become resistant to antibiotics over a short period of time.

28. Insecticide resistance
Insects become resistant over a short period of time
insecticide didn’t kill all individuals
resistant survivors reproduce
resistance is inherited
more of population is resistant
Resistance…
NOT immunity!
Insecticide & drug resistance
insecticide didn’t kill all individuals
resistant survivors reproduce
resistance is inherited
insecticide becomes less & less effective
Insecticide becomes less and less effective.